@JacobG Just caught up on all of this chat. Interesting problem you have. I think you are on to something about focusing too much on one issue and hoping the rest will follow -- I think you need to start with why and build out each issue from there. You need to unite them behind a common cause.

Maybe they need to realize that the other departments see them as difficult to work with -- ask them why they think that is and meet them half way. Ask them if they can agree they should be doing some things better, and let them know you'll help resolve issues that they have, too.

Also, read this book if you haven't: amazon.com/The-Five-Dysfunctions-Team-Leadership/dp/0787960756 It's a really quick read and it's a fictional story about a manager who comes in to fix a totally dysfunctional team. Most of the team members are rescuable but some aren't.